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A066462
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Numbers n such that EulerPhi(sigma(EulerPhi(n))) = sigma(n).
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1
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1, 5, 221, 763, 2759, 11303, 12749, 13079, 20677, 33725, 42253, 75101, 96193, 140225, 160369, 168113, 171667, 195889, 227099, 229969, 269161, 275971, 316129, 344317, 385033, 387163, 392677, 437999, 498253, 528209, 562913, 611381, 661181
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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LINKS
| Harry J. Smith, Table of n, a(n) for n=1,...,771
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MATHEMATICA
| Select[Range[1, 10^6], EulerPhi[DivisorSigma[1, EulerPhi[ # ]]] == DivisorSigma[1, # ] &]
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PROG
| (PARI) { n=0; for (m=1, 10^9, if (eulerphi(sigma(eulerphi(m))) == sigma(m), write("b066462.txt", n++, " ", m); if (n==1000, return)) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Feb 16 2010]
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CROSSREFS
| Sequence in context: A159317 A024070 A050617 * A046193 A195633 A112999
Adjacent sequences: A066459 A066460 A066461 * A066463 A066464 A066465
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KEYWORD
| nonn
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AUTHOR
| Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Jan 02 2002
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